Welcome to Book of the Week – a weekly feature offering you a glimpse between the pages of an Acres U.S.A. published title.

This week's Book of the Week feature is The Biological Farmerby Gary Zimmer. 

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From Chapter 15: Choosing the Right Seeds

What seeds should a biological farmer choose? The number of choices has grown dramatically in the past decade, with new hybrids, new open-pollinated varieties, and many new strains of genetically modified seeds hitting the market all the time. But the big question for many farmers today is whether or not to plant GM (genetically modified) seeds. A lot of controversy surrounds genetic modification, and while some farmers consider the engineered traits to be a huge benefit to their operation, others think they are not worth the added cost or have potentially harmful side effects.

When considering the wide variety of options available, what factors should a farmer take into account when choosing seeds? Cost? Return on investment? Convenience? Using the latest technology? Potentially using less insecticide or herbicide? Environmental benefits, or environmental harm? And the question I am often asked: Can a farmer use GM seeds and still be a good biological farmer?


Many available resources cover what GMOs are and how they are created. Basically, GMOs are organisms with artificially modified genetic material. Most genetic modification of crop plants involves inserting genes with desirable traits from one organism into the genome of another. Using corn as an example, this can mean inserting genes from a different type of plant, a bacteria, or any other type of organism into the corn plant, or it can mean deleting certain genes from the corn plant. This practice differs from traditional plant breeding, which involves selecting plants that have desired traits and breeding them to other plants with desired traits. I am not going to go into detail here about the genetic modification process because a lot of research and literature out there can explain it better than I can. I am more concerned about the pros and cons of using GMOs and what farmers need to think about before deciding if planting GM seed is a good fit for their farm.


Most information you’ll read on this subject will be heavily biased either in favor of using GMOs (without genetic modification wec ould never feed the world!) or strongly biased against GMOs (genetic modification is creating superweeds and unknown chemical by-products in our food that are terrible for our health!). Literally hundreds and hundreds of articles have been written about the pros and cons of GMOs, many of them either very emotionally based or funded by the companies that create GM plants and sell GM seed. In order to cut through all of the noise, I think farmers need to focus on a few key questions:

  • Do GM seeds yield better?
  • Can I reduce my insecticide and pesticide use if I plant GM varieties?
  • Are there any environmental consequences from planting GM varieties?
  • Is it worth spending the extra money for the GM seed? Will I make more money in the end?
  • With healthy, mineralized soils do I really need to use GM plants, and will they be a benefit?

I recently read an editorial by Jim Gerrish in the December 2015 issue of Stockman Grass Farmer about GMOs that explains this issue about as well as anyone can, and I highly recommend the article.

What is obvious to me, and to Jim as he explains it in his article, is that the new world of GMOs didn’t live up to its promises. Genetic modification was supposed to make farming cleaner and easier, with hardier, more stress-resistant plants and a reduction in the amount of chemicals needed. The reality is that more chemicals are being used than ever before, with many unintended consequences such as herbicide-resistant superweeds and almost total control of agricultural seeds by a very few companies. Put together with the higher seed costs and the strong consumer push against GMOs, I believe it is best to learn to farm without them where possible.

As an organic farmer, I don’t have the option of using GMOs, but I certainly don’t wake up in the morning thinking, “If only I could use GMOs, my farm would be so much better!” I simply don’t have the need for them. Healthy soils lead to healthy crops and healthy livestock. On a successful biological farm, the traits offered by the current genetically modified varieties of plants just aren’t needed.

There is also the issue of the extra cost to buy seed technology. With my current farming system, I don’t pay any tech fees on my seeds, or have the added cost of chemicals and commercial fertilizers. I know many other farmers who keep their seed costs low, use low rates of herbicides, reduced nitrogen rates, and rarely see the need for insecticides or fungicides. These are real cost savings on products that will never make the farm better for next year or the year after. By using better sources of minerals, rotating crops and adding cover crops to increase plant diversity, and using tillage practices that fit my soil type and keep my soil loose and crumbly, I keep my farm healthy and profitable without the added technology. This is how biological farming works, and it not only produces excellent crops, it also improves farm profitability.


When it comes to selecting seeds, I put a lot of effort into testing different varieties on my farm. As an organic farmer, I plant my corn later in the season, so I look for seeds that have fast emergence, early vigor, and grow into large plants that shade out the weeds. I also like flex varieties because I lose a number of plants with cultivation and other weed control methods. The genetic potential of most crop plants is far greater than the actual yield farmers are getting. Some companies’ genetics seem to work better on my farm than others, so each year I like to plant three varieties of the old standbys that I know do well, and then test one or two new varieties. I select for early dry down and shorter day length for early harvest so I can plant cover crops and have time for fall soil management. I like to have disease resistance bred into my plants, but with my farming system I don’t depend on it. My ninety-five-day corn probably has a yield potential of 250 bushels per acre, but I am happy getting 200 bushels. My neighbors plant 110-day corn with hopes of getting 200-bushel corn on their best land. But what is their limiting factor? Is it the corn variety? Or is it using too much or not enough fertilizer, or the wrong type of fertilizer?

Maybe they need soluble calcium and aren’t addressing it. Or is it their tillage program, or maybe the lack of plant diversity? There are often bigger issues limiting yield than plant genetics.

About fifteen years ago I started a project with an alfalfa breeding station to select varieties of alfalfa that grew well on a biologically farmed, mineral-balanced soil. The current system for breeding alfalfa selects varieties that can tolerate how the land is farmed and the types of fertilizers used. When the soil is in poor shape and the breeding station is only applying 0-0-60, the alfalfa varieties grown there are selected to do well on those soil conditions. I didn’t like the soil conditions or the conventional fertility program on the breeding station, so I worked with them to change things. In the beginning, they applied six hundred pounds per acre of 0-0- 60 and sprayed insecticides and herbicides on a regular schedule along with using a sump pump to remove standing water from the field after a rain because of poor soil structure. Under my recommendations, they applied a balanced fertilizer, grew cover crops and shallow-incorporated them, and subsoiled when needed. The following table shows the fertility program I set up on the farm compared to what they had been doing on their alfalfa:

The results achieved by changing to a biological farming system were astounding. The soil structure is now beautiful, and the station no longer needs the sump pumps because the soil drains well, even after a heavy rain. They also rarely need an insecticide or fungicide and have cut way down on the use of herbicides. The alfalfa variety that did best on these higher quality soils was not the strain that did best in the conventionally farmed plots — it was a variety that thrived and produced very high yields in good quality soils with adequate calcium exchange. I have been marketing this variety and working with the breeding station on improving it for over ten years now.

Fertilizer comparison

It is a showy alfalfa that’s hard to beat if you’re following a biological farming program. The breeding station managers were so impressed by the change in soil quality that they switched the whole farm to biological, and now most of the varieties on the breeding station are yielding around 40 percent more with fewer disease and insect problems. I am now looking into breeding corn varieties following this same protocol of finding plants that do the best under a biological farming system.

I select the genetics I use on my farm for a reason: yield, standability, maturity, quality, production, and general overall appearance. In the future we will select cover crop seeds in a similar way, based on plant performance. Right now most seed is sold based on price or marketing of a new trait. What if I could select certain genetics to do a particular job on my farm and fit the farm’s soils? It would be a very different way of looking at seed selection, and I think one that would lead to better results.


Genetics are important, and you should pay attention to what seeds you plant, but they are not the limiting factor on most farms. Work to remove the constraints on your farm that prevent optimal production and require you to use plant protection chemicals. In most cases, those constraints are limiting your yield and profitability more than your seed varieties. Do you really believe that these new super genetics are silver bullets that will solve all your problems? Farming with healthy, mineral-balanced soils and attention to both soil and plant quality is the only thing that will get you bumper crops and reduce pest and disease problems.

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About the Author:

Gary Zimmer is an organic dairy farmer, an accomplished speaker, a sought-after farm consultant and president of Midwestern BioAg, a biological farming products and services company. He is also the author of Advancing Biological Farming, a sequel to The Biological Farmer.

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Be sure to check out the Gary Zimmer audio collection for a complete selection of his previous Eco-Ag Conference seminars!

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